EXPLAIN¶

You can prepend any SELECT statement with the keyword EXPLAIN to display the physical plan that is used during the execution.

Syntax¶

PLAN
A textual representation of the plan
PLAN_HASH
A hash that allows to quickly disambiguate between two plans
PLAN_DOT
A dot representation of the plan
PLAN_GML
A Graph Modelling Language (GML) representation of the plan
PLAN_CONTINUATION
A byte array that contains information that is essential in the context of plan serialization

TODO change examples to render dot graph and put actual plan hash

EXPLAIN SELECT name FROM restaurant WHERE rest_no >= 44;

`PLAN`	`PLAN_HASH`	`PLAN_DOT`	`PLAN_GML`	`PLAN_CONTINUATION`
SCAN(<,>) \| TFILTER RestaurantComplexRecord \| FILTER _.rest_no GREATER_THAN_OR_EQUALS 42 \| MAP (_.name AS name)	`-1635569052`	dot_graph	gml_graph	continuation

EXPLAIN
    SELECT name
    FROM RestaurantComplexRecord USE INDEX (record_name_idx)
    WHERE rest_no > 10

`PLAN`	`PLAN_HASH`	`PLAN_DOT`	`PLAN_GML`	`PLAN_CONTINUATION`
COVERING(record_name_idx <,> -> [name: KEY[1], rest_no: KEY[2]]) \| FILTER _.rest_no GREATER_THAN 10 \| MAP (_.name AS name)	`-1543467542`	dot_graph	gml_graph	continuation

EXPLAIN
    SELECT *
    FROM RestaurantComplexRecord AS R
    WHERE EXISTS (SELECT * FROM R.reviews AS RE WHERE RE.rating >= 9)

`PLAN`	`PLAN_HASH`	`PLAN_DOT`	`PLAN_GML`	`PLAN_CONTINUATION`
ISCAN(mv1 [[9],>) \| MAP (_.0 AS rest_no, _.1 AS name, _.2 AS location, _.3 AS reviews, _.4 AS tags, _.5 AS customer, _.6 AS encoded_bytes)	`-8677659052`	dot_graph	gml_graph	continuation